It allows parsing tools (for example other websites, or browser add-ons[1] like Firefox's Operator extension) to extract the details of the event, and display them using some other website, index or search them, or to load them into a calendar or diary program, for instance. Multiple instances can be displayed as timelines.

<pclass="vevent">
The <spanclass="summary">English Wikipedia was launched</span>
on 15 January 2001 with a party from
<abbrclass="dtstart"title="2001-01-15T14:00:00+06:00">2pm</abbr>-
<abbrclass="dtend"title="2001-01-15T16:00:00+06:00">4pm</abbr> at
<spanclass="location">Jimmy Wales' house</span>
(<aclass="url"href="http://en.wikipedia.org/wiki/History_of_Wikipedia">more information</a>)
</p>

Note the use of the abbr element to contain the machine readable, ISO8601, date-time format for the start and end times.

Concerns have been expressed[2] that, where it occurs, the use of the abbr element (using the so-called abbr-design-pattern) in the above manner causes accessibility problems, not least for users of screen readers and aural browsers.[3] The newer h-event microformat therefore uses the HTML5 element time instead: